Method of Synthesizing Hybrid Metal Oxide Materials and Applications Thereof

ABSTRACT

The present invention relates to metal oxide coating materials that can be used as thin film thin film coatings on various substrate surfaces. The invention also concerns a method of making metal oxide material which are stable in aqueous phase and that can be deposited on a substrate by liquid phase deposition, such as spin-on deposition. The new materials can be patterned lithographically or non-lithographically and are applicable for building up various electronic and opto-electronic device structures, such as anti-reflection layers, high-k interlayer and gate oxide structures for ICs, etch stop layer, CMP stop layer, solar cells, OLEDs packaging, optical thin film filters, optical diffractive grating applications and hybrid thin film diffractive grating structures.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to metal oxide coating materials that canbe used as thin film coatings and lithographically ornon-lithographically patternable thin film coatings on various substratesurfaces. Furthermore, the invention concerns materials that can be usedfor building up various electronic and opto-electronic devicestructures. The invention also deals with methods of making metal oxidematerials.

2. Description of Related Art

As known in the art, organo-modified silicon dioxides can be employedfor forming optically transparent and electrically well insulatinglayers by using them as organo-siloxane polymers, also known as “sol-gelpolymers”. For example, in the simplest case, silicon tetraethoxide orsilicon tetrachloride is hydrolysed and condensation polymerisation ofthe hydrolysed monomer results in a siloxane polymer that can beconverted to a silicon dioxide material under thermal treatment.Furthermore, organo-siloxanes can be made lithographically patternableby attaching photo-crosslinking moieties covalently to the silicon oxidebackbone. A silicon oxide material based on pure silicon dioxide or evenorgano-modified silicon dioxides exhibit, however, a relatively lowrefractive index. Refractive indices of these materials are typicallyaround 1.5 and their dielectric constants are in the range from about4.2 to 2.5 depending on their structure and on the moieties attached tosilicon. When silicon is replaced by other elements of the periodictable of elements that have a higher number of electrons, such asgermanium, titanium, tin, antimony, tantalum, hafnium or zirconium, muchhigher refractive indices as well as dielectric constants can beobtained.

SUMMARY OF THE INVENTION

It is an aim of the present invention to eliminate at least some of thedrawbacks of the prior art and to provide a method of producing acomposition, which can be applied on a substrate to form a metal oxidecoating material on said substrate.

It is another object of the invention to provide a coating composition,comprising stabilized monomers dissolved in an aqueous or in an organicsolution.

It is a third object of the invention to provide a method of forming athin film on top of a substrate.

These and other objects, together with the advantages thereof over knownmethods and compositions, are achieved by the present invention ashereinafter described and claimed.

The present invention is based on the idea of providing a complex metaloxide precursor composition which can be processed in liquid phase.

It has been found that precursors of metal oxide materials used forforming a metal oxide film on a substrate can be stabilized by reactingthem with an organic compound, which is capable of reacting with theprecursor by forming a chemical compound or a chemical complex. Theformed chemical complex is soluble in a low-boiling solvent, preferablyin water, and can be recovered in the form of an aqueous solution. Whennecessary, the processing solvent can be solvent-exchanged for asolvent, with more suitable properties, such as a higher boiling point.

In the invention, complex metal oxide precursor compositions are used asprecursors of the metal oxide materials. Such complex compositionstypically comprise at least two different metal oxide precursors,comprising different metals or the same metal but with differentinorganic or organic residues bonded to the metal or combinationsthereof. The complex composition may also comprise precursor molecules,which contain at least two kinds of inorganic or organic residues. Suchprecursor materials are converted into intermediate products, which aredissolved in liquid phase and which can be polymerized.

Described herein are also coating compositions, which comprise thereaction product between a metal oxide precursor and an organiccompound, which contains at least one functional group capable ofreacting with the metal element of the precursor. The composition isdissolved in a liquid, and the deposition of the material can beperformed, for example, from aqueous liquid phase. However, the materialcan be deposited from various other processing solvents when made stableby fixing the conditions (such as pH-value of the solution) to keep thehybrid metal oxide material stable in solution.

The present compositions can be utilized in a method of forming a thinfilm on top of a substrate. In the method of forming a thin film, on thesurface of the substrate there is applied a composition obtained byconverting metal oxide precursors into an intermediate product, which isdissolved in liquid phase and which can be polymerized.

More specifically, the method of forming a thin film by what is statedin the characterizing part of claim 1.

The method of forming complex metal oxide precursor compositions ischaracterized by what is stated in the characterizing part of claim 25.

The present invention provides considerable advantages. Thus, highrefractive index and high dielectric constant coatings and structurescan be fabricated at relatively low temperatures (e.g. 150° C. or as lowas 50° C. and above), which enables their use on various substrates,even on plastic and paper. The refractive index of the material can betailored by selecting the metal oxide precursor for the synthesis.Synthesis can be carried out using a single metal oxide precursors, butit is also possible to introduce two or more different metal oxideprecursors to the material. This gives also possibility to tailor theoptical properties and electrical and thermal conductivity properties ofthe produced films. In addition to using more than one metal oxideprecursor it is possible to introduce organic components to metal oxideprepolymers. The organic moieties can be used to facilitate e.g.photopatternability of the final deposited material film. The introducedorganic moieties can be also used to adjust the processability andstability of the final synthesized material. Also the described coatingscan be made to be very efficient abrasion resistant coatings.

The material can be easily processed with various patterning methods.The invention makes it possible to process metal-oxide films fromaqueous solutions. Materials are obtained that can be cross-linked by UVvia the attached organic moieties.

Next, the invention will be examined in more closely with the aid of theattached drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts diagrammatically the extinction co-efficiency of titaniumoxide films annealed at 150° C. and 350° C.;

FIG. 2 depicts diagrammatically the refractive index of titanium oxidefilms as a function of wavelength for 150° C.° (solid) and 350° C.°(dashed) annealed films;

FIGS. 3 a and 3 b depicts the results of surface-topography measurementsof deposited films, whereat FIG. 3 a shows a 3D image of the filmtreated at 150° C., and FIG. 3 b shows a 3D image of the film treated at350° C.;

FIG. 4 shows in a schematical fashion the various steps of lithographicprocessing of negative tone materials;

FIG. 5 shows in a sectional sideview a lithographic multilayeredstructure containing BARC or TARC layers formed by lithographicprocessing;

FIG. 6 shows in a sectional sideview the structure of an opticalcomponent with overlaying ARC layer(s);

FIG. 7 shows in a sectional sideview an organic light emitting structurecontaining an overcoat/seal of the present material;

FIG. 8 shows in a sectional sideview of a multilayered solar cell,containing a material layer formed as an efficiency-enhancing layerbetween the anode and organic material of the cell;

FIG. 9 depicts in sectional sideview an exemplifying embodiment of athin film filter;

FIGS. 10 a and 10 b show in sectional sideview and top view,respectively, the structure of a stack filter;

FIG. 11 shows in a sectional sideview the structure of an alternativeembodiment of a thin film filter;

FIG. 12 shows in a sectional sideview the structure of a multilayeredresonant cavity for an OLED; and

FIG. 13 gives a schematic depiction of the synthesis of the metal oxidehybrid polymers.

DETAILED DESCRIPTION OF THE INVENTION

As discussed above, it is an object of the invention to provide asynthesis and fabrication method for high quality, high refractive indexand high dielectric constant hybrid metal oxide materials, coatings andstructures.

According to one embodiment for converting the metal oxide precursormaterial into intermediate products which are dissolved in liquid phaseand which can be polymerized, typically comprises the steps of

-   -   providing a complex metal oxide precursor composition with at        least one precursor, containing a single metal element, or a        preformed precursor, which contains a combination of two or more        metal elements;    -   providing an organic compound, which contains at least one        functional group capable of reacting with the metal element, or        with at least one metal element, of the precursor;    -   reacting the precursor, or at least one precursor, with the        organic compound, preferably in a liquid medium to provide a        reaction product; and    -   recovering the reaction product.

Within the scope of the present invention, the term “precursor” is usedto designate any compound, which contains the metal of the metal oxidematerial in such a form that the metal atom is capable of reactingduring the subsequent processing stages by forming a metal oxidenetwork. The precursor is included in a “complex metal oxide precursorcomposition” which will be described in more detail below in connectionwith formulas I to III.

Typically, the precursor and the organic compound are mixed together ina liquid medium, or the precursor is dissolved in the organic compound,to provide a reaction mixture and the reaction is allowed to proceed inthe reaction mixture for a reaction time of 0.1 to 24 hours. Thereaction can be carried out in one step or as a multistep reaction. Inthe latter alternative, the reaction is, for example, first allowed toproceed for about 0.05 to 5 hours under intensive stirring. Then, thereaction mixture is allowed to stand for the remainder of thepredetermined reaction time. The reaction temperature is usually ambientor elevated, preferably it is about of 10 to 80° C.

The reaction product comprises an intermediate product formed by theprecursor, which is at least partially hydrolyzed, and the organiccompound, which is bonded or coordinated to the precursor. Thus, thesynthesis of the reaction product is based on hydrolysis andcondensation chemistry synthesis technique; the precursor is preferablyreacted with the organic compound in the presence of a sufficient amountof water to hydrolyze at least a part of the precursor.

According to a preferred embodiment, the reaction is carried out inaqueous phase, e.g. by mixing the precursor with the organic compound inwater to form an aqueous solution. It is also possible to carry out thereaction in an organic solvent, which contains a sufficient amount ofwater. The organic solvent can comprise the organic compound used forforming the reaction product. Optionally, an excess of the organiccompound is then used. The amount of water is typically at least 4-fold,preferably at least a 10-fold, compared to the equivalent amount basedon hydrolysable groups of the metal oxide precursor. The water neededfor the hydrolysation can also be provided by crystallization waterliberated from a metal salt.

In many cases, the metal oxide precursor is highly reactive towardswater and it can be advantageous to dissolve or dilute the metal oxideprecursor in an organic solvent to reduce reactivity before theprecursor is contacted with the organic compound and/or water. Typicalorganic solvents which can reduce reactivity include chlorinated andfluorinated hydrocarbons, such as chloro-substituted alkanes(chloroform, dichloromethane and dichloroethane). Also toluene andxylene can be used as solvent.

According to the invention, the preferred method of forming anintermediate compound comprises the steps of

-   -   providing at least two starting reagents, at least one of which        comprises a metal oxide precursor;    -   reacting the reagents with each other to form a reaction product        comprising a modified metal oxide precursor;    -   recovering the reaction product; and    -   reacting the reaction product with a compound selected from the        group of organic compounds, water and aqueous solutions, for        converting the reaction product into an intermediate product        which is suitable for liquid phase processing.

Optionally, the reaction product can be reacted with both organiccompounds and water or aqueous solutions, sequentially or simultaneouslyto obtain conversion and stabilization along with hydrolyzation of theprecursors.

The intermediate product is capable of polymerizing to form a film. Inparticular, the intermediate product is capable of polymerizing underthe influence of heat and optionally evaporation of solvent. Other waysof polymerizing the intermediate product (prepolymer) include the use ofradiation and photoinitiators. Also thermal initiators can be used.

Thus, the intermediate product is capable of polymerizing to form across-linked polymer having a (weight average) molecular weight inexcess of 5,000 g/mol and up to 250,000 g/mol. Typically, the reactionproduct therefore comprises a prepolymer having a (weight average)molecular weight of 200 to 5000 g/mol.

According to the present invention, the metal oxide precursor is a“complex metal oxide precursor composition”, which preferably comprisesat least two compounds selected from the group of metal halogenideshaving the formula IMeX_(m),  I

-   -   wherein Me stands for a metal, X stands for a halogenide and m        represents the valence of the metal, and        metal alkoxides, having the formula II        MeOR¹ _(m)  II    -   wherein R¹ stands for a linear or branched, aliphatic or        alicyclic alkyl group, which optionally is substituted by 1 to 3        substitutents selected from the group consisting of hydroxy,        carboxy, anhydride, oxo, nitro and amido groups, and Me and m        have the same meaning as above.

Me is preferably selected from the group consisting of germanium,titanium, tin, antimony, tantalum, hafnium, zirconium and silicon. X ispreferably a chloride. Any alkoxide is suitable, but preferablymethoxides or ethoxides are used due to their reactivity.

The metal oxide precursor can comprise two or more metal halogenides ofthe formula I or metal alkoxides having the formula II, having differentmetal elements Me. In the latter alternative, the metal oxide precursorcomprises, for example, a second metal oxide precursor having theformulas I or II, wherein the metal stands for lanthanum, indium orlead. Naturally, mixtures of metal oxide halogenides/alkoxides of theabove groups of germanium, titanium, tin, antimony, tantalum, hafnium,zirconium and silicon can also be employed. The metal oxide precursormay also comprises a metal halogenide or metal alkoxide, which in itselfcontains two different metal atoms.

Furthermore, the metal oxide precursor may comprise a second metal oxideprecursor containing nitride or silicide groups.

Another alternative comprises metal oxide precursors having the formulaIIIX_(n)MeOR¹ _(p),  III

-   -   wherein Me, X and R¹ have the same meaning as above and n is an        integer 0 to m, p is an integer 0 to m, and the sum of n+p is        equal to m, m having the same meaning as above.

The complex metal oxide precursor composition can also comprise amixture of compounds according to at least one of formulas I and II withat least one compound of formula III.

In the complex metal oxide precursor composition, containing two or morecompounds according to formulas I and II and optionally III, the molarratios between the different compounds can vary within a broad range.Typically, there are two different kinds of molecules present in molarratios of about 1:1000 to 1000:1, preferably about 1:100 to 100:1, inparticular about 1:10 to 10:1. Equimolar amounts are usually convenient.

According to the invention, it is possible to stabilize at least one, orpreferably all metal oxide precursors, by using an organic compound. Theorganic compound is selected such that it is capable of stabilizing themetal oxide precursor to the extent that it does not form a fullycross-linked polymer matrix, which would not be solvable in an aqueousor organic solvent.

In general, the organic compound needs to be reactive with the metalelement used in the synthesis and to be able to stabilize the metaloxide precursors so that they do not form a fully cross-linked “jelly”type polymer matrix, which is not soluble in aqueous or organicsolvents. Within the scope of the present invention, the term “reactive”means that the organic compound is capable of forming a chemicalcompound or a chemical complex with the metal oxide precursor. For thatpurpose, the organic compound should have at least one, preferably 1 to3, functional groups capable of reacting with the metal oxide precursor.Examples of such groups are carboxy, carboxylic anhydride, oxo, amideand nitro groups. A further feature is that the organic compound maycontain groups, which can induce cross-linking reactions during anannealing or polymerization stage. For example, the organic compound maycontain carbon-carbon double bonds.

In the below example, methacrylic acid is used, but the invention is notlimited to such stabilizing and complexing organic compounds.Preferably, the organic compound can be any organic compound selectedfrom the group consisting of organic acids, acid anhydrides, alkoxides,ketones, beta-diketones, acetyl acetones, benzyl acetones, aryl oxides,beta-keto-esters, alkanol amines, glycols, oximes, alkyl hydroxylamines, beta-keto-amines, Shiff-bases, thiols and aldehydes. Therefore,examples of suitable organic compounds include, but are not limited to,acetic acid, acrylic acid, metacrylic acid, trifluoroacetic acid.Further examples are formed by ketones, such as acetone, andbeta-diketone, and aldehydes.

During the reaction, the molar ratio between the metal oxide precursorand the organic compound is about 10:1 . . . 1:10, preferably about 5:1to 1:5. Suitably, the molar amount of the organic compound is at leastequal to the valences of the metal in the metal oxide precursor.

After the reaction, the reaction product is recovered. Since it isgenerally soluble in the reaction medium, it is recovered in solution,e.g. in an aqueous solution. It can also be recovered in the solutionformed by an organic solvent and then dissolved into an aqueous phase bysolvent displacement. It is also possible to recover the reactionproduct in aqueous solution and dissolve it into an organic solventhaving a boiling point higher than water by solvent displacement. As anexample of such a solvent, cyclic ethers, such as gamma butyrolactone,can be mentioned. Furthermore, solvent mixtures can be used asprocessing solvent.

FIG. 13 gives a schematic depiction of the synthesis of the metal oxidehybrid polymers. This synthesis method can be used for the abovementioned metal oxide precursors, using one or two metal element Meprecursors (same metal or different), pure halogenides or alkoxides or acombined precursor having both halogenides and alkoxides as ligands.Thus, it can be applied to the preparation of single metal oxideprecursor compositions or complex, multi-metal oxide precursorcompositions. The synthesis method varies from case to case depending onthe precursors used (solubility, reactivity), need for neutralizationprocedure of the material, organic compound used and selection of thefinal processing solvent for the material (aqueous, organic).

In the following, the synthesis method flow is described in general withreference to FIG. 13 and using titanium oxide as an example. Below threedetailed examples are given.

Step A:

In step A the starting reagents are reacted with each other. Reagents R1and R2 can both be metal oxide precursors having different or the samemetal element Me; they can be pure halogenides or alkoxides or combinedprecursors having both halogenides and alkoxides as ligands. Thereaction can be carried out in an inert solvent, if preferred. In somecases the reaction can be carried out by using a metal element precursoras Reagent R1 and a reactive solvent (e.g. an alcohol) as Reagent R2. Insuch a case, if Reagent R1 is, e.g., titanium tetrachloride (TiCl₄)which is reacted with ethanol (EtOH, R2), Product 1 (P1) from thisreaction is a “combined” substituted titanium precursor e.g.TiCl₂(OEt)₂. This reaction also produces hydrochloric acid HCl (S1) as aside product.

Typically if an inert solvent is used in step A it is removed once theReagents R1 and R2 havereacted (before step B).

Step B:

Typically the Product 1 (P1) at this stage of the synthesis has thegeneral formula X_(m)MeOR¹ _(m), or X_(m)MeO_(m)MeOR¹ _(m), wherein X,Me and R¹ have the same meaning as above.

Now the pre-reacted starting precursor can be dissolved in a solvent andreacted optionally already at this stage with organic compounds (to formdifferent complexes), water or acidic water (to induce hydrolysis andcondensation of the metal oxide precursors). In some cases where it ispreferred to fully neutralize the material, and if Product 1 (P1) stillcontains halogenide ligands, the reaction of P1 is preferably continuedfurther. This can be done e.g. by adding a stoichiometric amount ofdistilled water into the reaction mixture. For the materials mentionedabove in Step A, this reaction produces a reaction Product (P2), basedon the following equation:Ti(OH)₂(OEt)₂(TiCl₂(OEt)₂+2H₂O->Ti(OH)₂(OEt)₂+HCl,and a Side Product (S2), e.g. HCl.Step C:

When halogenide metal precursors (e.g. chloride) are used in thereaction Reaction products (P2 and P3) are usually very acidic aftersteps A and B. This is due to the side products (S1 and S2, e.g. HCl)formed during the synthesis. The material can be neutralized at thispoint using, e.g., triethylamine (NEt₃) in the reaction. Otherneutralazation procedures can also be applied. NEt₃ reacts with HClforming Et₃N.HCl (Side product S3). When the reaction is carried out ina suitable solvent, Et₃N.HCl precipitates out and can be removed usingfiltration.

Step D:

The material is filtrated using, e.g., pressure filtration orrecirculation filtration.

Step E:

In some cases, at this stage the material is ready for use without theneed of any further additives. It may be required to change the solventused during the synthesis to a more suitable solvent for processing.This can be done using a solvent exchange procedure.

In some cases it is preferred for reasons of materials processing andstability to react the metal oxide material with organic compounds (toform different complexes and stabilize the material) and with acidicwater (to induce hydrolysis and condensation of the metal oxideprecursors). If organic compounds and acidic water are added, as a laststep usually the acidic water is removed from the material usingdistillation. Also the synthesis solvent can be changed to a moresuitable solvent for processing purposes.

As evident from the above, a coating composition according to thepresent invention comprises, according to one embodiment, the reactionproduct between a metal oxide precursor and an organic compound anorganic compound, which contains at least one functional group capableof reacting with the metal element of the precursor. The coatingcomposition contains about 0.001 to 10 moles/l of the reaction product.Generally, the concentration of the reaction product in the liquidcomposition is about 0.1 to 60 wt-%, in particular about 5 to 50 wt-%.It is also possible to evaporate off the solvent/liquid of the recoveredproduct to obtain an dry or semi-dry product, which can be dissolved ina solvent suitable for the subsequent film forming processing step.

The solution obtained (either aqueous or in an organic solvent) can beused as such for deposition by, e.g. liquid phase spin-on deposition,dip-coating, spray coating, menicus coating, gravure and/or flexographiccoating.

The film-forming method comprises the steps of

-   -   applying on the surface of the substrate a coating composition,    -   forming a thin layer on the surface;    -   removing the solvent of the solution; and    -   polymerizing the intermediate product into a solid film.

The substrate is typically selected from the group of glass, plastics,paper, ceramics and laminates.

Generally, the reaction product can be processed to from liquid phase toresult in film thicknesses ranging from 1 nm to 1000 nm with singledeposition run. If high processing temperatures are required filmthickness is preferably below 500 nm to prevent film failure duecracking.

The concentration of the composition during application depends on thetarget thickness of the film. By diluting the composition, it becomespossible to form thinner films. Generally, a concentration of about 5 to30 wt-% is preferred.

If thicker films are required with a single deposition run the amountand type of solvent in the material can be varied. Furthermore, theaqueous solvent can be replaced with a suitable organic solvent, ifnecessary. For example, gamma-butyrolactone is a suitable solvent to beused with the present metal oxide hybrid polymers. Gamma butyrolactonecan be used by itself or as a mixture with water.

By varying the amount of processing solvent it is possible, e.g., tofabricate titanium oxide hybrid polymer film in excess of 1000 nm inthickness. However, if high processing temperatures (350° C. or higher)are required, the achievable film thickness is in the range of 300 to600 nm with single spin process. If various deposition runs are made,thicker films can be achieved.

A thin film layer thus formed can be annealed at low temperatures toresult in high refractive index and high dielectric constant coatings.Thus, to mention an example, for titanium oxide hybride materials, arefractive index of 1.94 (typically 1.9 or higher) can be achieved at atemperature of 150° C., and when the temperature is increases to 350°C., a refractive index of 2.03 (typically 2.0 or higher) can beachieved.

Generally, when the thin layer is annealed at a temperature in the rangeof 80 to 350° C. a metal oxide film is produced, which contains at leastsome residues of the organic compound. However, when the organiccompound contains radiation sensitive carbon double bonds polymerizationof the intermediate product can also be carried out photo-crosslinking,as discussed above.

Depending on the application the formed film can also be annealed atvery high temperatures (500 to 1000° C. or higher) to fully remove theorganic compound (e.g. methacrylic acid) from the film leading toformation of a metal oxide thin film.

The hybrid metal oxide materials described herein can be patterned usingUV-lithography, embossing, hot-embossing, UV-embossing, flash and print,nano-imprinting, roll-to-roll printing and gravure printing.

Since the materials can be cured at low temperature during theprocessing the use of various substrates types, such as plastics andpaper, is possible.

The various applications of the invention will be examined below.Summarizing, it can here be noted that the present coating(film-forming) compositions according to the invention can be used forforming an optical or electrical thin film coating on a substrate, forforming a high refractive index film on top of a grating structure, forforming a high dielectric constant film (k value in excess of 3.9), forforming anti-reflection coatings, for forming a chemical and dry etchingstop layer in lithographic processing, for forming a protective coatingin an organic light emitting device, and for forming an efficiencyenhancing layer in a solar cell. Further, the invention can be used forforming a high index material in an optical thin film filter and forforming an optical diffractive grating and a hybrid thin filmdiffractive grating by embossing, holography lithography andnano-imprinting of the thin film.

The present materials also form excellent high refractive index abrasionresistant coatings.

The following non-limiting example discloses the preparation of the newcoating compositions:

EXAMPLE 1 Titanium Hybrid Polymer

Synthesis:

The liquid phase material for hybrid titanium oxide films wassynthesized by using hydrolysis and condensation chemistry for titaniumchloride precursors. Thus, 0.4 mol of titanium tetrachloride wasstabilized and complexed with 0.1 mol of methacrylic acid

The solution was hydrolyzed with a 10-fold molar excess (in respect tothe chloride ions bonded to titanium) of ultra pure water, containingless than 10 ppm of impurities, with dichloromethane as an organicsolvent reservoir and reaction stabilizer. The solution was allowed toreact for 2 hours under vigorous stirring and in addition the solutionwas allowed stand still additional 12 hours without stirring. Finally,the aqueous phase was extracted from the solvent by an extraction funnelresulting in a stable aqueous liquid form material that was ready forspin-on deposition.

Processing (Example of Spin-On Deposition):

For testing purposes above-mentioned titanium oxide hybrid polymer wereused as an optical thin film and thus the films were deposited on p-type4″ and 6″ silicon substrates by applying spin-on processing method. Thesolution was poured on a static substrate after which the material wasspun-on the wafer in two stages: first the solution was spread on thesubstrate with 300 rpm speed for 5 seconds and then the speed wasaccelerated in 2 seconds to 2000 rpm and allowed spin for 30 seconds.Edge bead removal (5 mm removal from the wafer edge) and backside rinsewere accomplished manually using 2-propanol as a rinsing solvent. Thefilm annealing was done with conventional open-air laboratory hot platewith ±2° C. temperature uniformity over the plate. Initial film pre-bakewas done at 60° C. for 5 minutes. Then the film was taken throughtemperature sequenced annealing process (85° C., 105° C., 150° C., 200°C., 250° C. and 350° C.) each for 5 minutes. Between each step the filmwas cooled down and optical measurements were carried out usingreflectometer. Moreover, two 6″ silicon wafers were fabricatedinterchangeably at 150° C. and 350° C. annealing forspectrophotometry-based metrology characterization. Adhesion and wettingability on a polypropylene plastic substrate was also tested wherein thewetting and the adhesion to a plastic type substrate was found be good.Finally, the films refractive index stability was tested with a“pressure cooking test” (120° C., ˜2 atm for 2 hours), wherein norefractive index changes were not observed.

Film Characterization:

The film thickness, refractive index and extinction coefficientmeasurements were performed by using Filmetrics 20 reflectomer and SClFilmTek 4000, which is a spectrophotometry-based metrology tool. Thespectral optical data was acquired from 200 nm to 1700 nm. Thesurface-topography and rms surface roughness values of the depositedfilms were characterized with an optical non-contact surface profiler(WYKO NT-3300).

The synthesized material was very reactive against elevated temperaturetreatments. The films annealed at 105° C. for 5 minutes, resultedalready as stable films that were resistant against common organicsolvents as well as acidic and basic aqueous solutions without anychanges in optical properties. In addition, the scratch resistance ofthe films annealed at 105° C. was excellent, although actual hardnessvalues were not acquired. Adhesion on both substrates, i.e.polypropylene and p-type silicon, was also found to be good for 105° C.treated samples as they passed standard “Scotch tape test”. Stability of150° C. and 350° C. annealed films were tested with “pressure cookingtest” where the samples are treated in 2 atm supercritical waterpressure at 120° C. for two hours. The test indicated that the filmsannealed at 150° C. or less are not fully densified to withstand veryaggressive environments, since the film's refracfive index degreasedmore than 1% or 2.1×10⁻² at 632.8 nm wavelength. However, the filmannealed at 350° C. showed good stability against the “pressure cookingtest” and index change was in the order of ±2×10⁻⁴ at 632.8 nm.

Extinction co-efficient (k) showed slight increment as a function ofannealing temperature as the film got more densified. At UV region (<400nm) the extinction co-efficient increased rapidly by reaching themaximum value at the end of the measurement range (250 nm). The k valuesat 250 nm range were 0.0125 nm⁻¹ and 0.0215 nm⁻¹, respectively, forsamples annealed at 150° C. and 350° C. Spectral extinctionco-efficiencies are presented in FIG. 1. The k value saturated to“zero-level” in terms of measurement accuracy (approximately 1.0×10⁻⁴)at 390 nm for both samples and no changes were obtained at visible andNear Infra-Red (NIR) regions up to 1700 nm (see insert in FIG. 1).

Spectral refractive indices between 250-1700 nm are shown in FIG. 2. Theannealing temperature has an analogous effect on the refracfive index ofthe films as on the extinction co-efficient values. Therefore higherrefractive index was obtained for the sample treated at 350° C.Refractive index difference between the annealing temperatures was0.0928 at 632.8 nm with corresponding values of 1.9407 and 2.0336 of150° C. and 350° C. treated samples, respectively. The indices reachedthe maximum at 290 nm for the lower temperature sample and at 285 nm forthe higher temperature sample, thereafter indices steadily degreased.The maximum values for 150° C. and 350° C. samples were respectively2.5892 and 2.8464.

The achieved film uniformity was better than 0.5% and 0.9% (five pointsmeasured over the wafer) on a 4″ and 6″ silicon wafers, respectively.The film uniformities are comparable to standard chemical vapordeposition or physical deposition based thin film processing techniques.The film treated at 150° C. resulted in a rms surface roughness of 1.43nm within a 400 μm×400 μm rectangular region, after tilt removal fromthe surface (see FIG. 3 a). The film treated at 350° C. resulted in arms surface roughness of 0.97 nm within a 400 μm×400 μm rectangularregion, after tilt removal from the surface (see FIG. 3 b).

Some film shrinkage was noticed between the films baked at 60° C. andfilms annealed at 350° C. The shrinkage of almost 50% for 350° C.annealed films can be explained by hydroxyl and methacrylic acid groupcondensation/cleavage reactions and evaporation of water solvent (a partwhich was not removed in the extraction) removal during the annealing atelevated temperature. The same reactions are also reasons for a surfacereflow and sintering, which resulted in better surface smoothness forthe high temperature annealed film. The effect of the shrinkage was alsoseen as relatively high birefringence of the films that is formedthrough stresses in the films. The optical birefringence for 150° C. and350° C. were 1×10⁻³ and 9×10⁻³, respectively. The film thicknesses as afunction of temperature are presented in Table 1. Table 1 presents alsorefractive indices for corresponding processing temperatures. TABLE 1Refractive indices (at 633 nm) of the film at various processingtemperatures and corresponding film thicknesses based on reflectomermeasurements. Annealing Film Thickness Refractive Index at Temperature(°^(°) C.) (nm) 633 nm 60 140 1.72 85 106 1.81 105 95 1.87 150 91 1.94200 85 1.97 250 77 1.99 350 73 2.03

The 350° C. anneal film was also tested by mercury-probe method fordielectric constant and the value was found be 72.

EXAMPLE 2 Titanium Oxide Hybrid Polymer 1

Ti(iOPr)₄ (0.05277 mol) was placed in a round bottom flask.TiCl₄(0.05277 mol) was added by syringe and needle. The solution containing awhite solid was stirred at room temperature (RT) for 10 min. 125.04 g of2-isopropoxyethanol was added and the clear yellow solution was stirredat room temperature for 30 min. (Nd=1.4332). 3.80 g of H₂0 (0.21099 mol)was added and the reaction solution was stirred at room temperature foran additional 5 min (Nd 1.4322). 21.36 g of TEA (0.211088 mol) was addedto neutralize the reaction mixture. The obtained white suspension wasstirred at room temperature for 2 h. The wWhite reaction suspension wasfiltrated using pressure filter (filter paper size 0.45 um) Nd=1.4235and pH=6.5-7 (pH-paper was used for determination). The amount ofmaterial in grams after filtration was 92.71 g. An acidic water solution(nitric acid, HNO₃, 0.0652 mol) was added to the reaction mixture. Then,metacrylic acid MAA, 0.1304 mol) was added dropwise after a few minutes.The reaction mixture was stirred at room temperature over night.Finally, the acidic water was removed by using rotary evaporator[evaporation, pressure=77 mbar, t(bath temp)=48° C., t=10 min. pH=5.01,Nd=1.4255]. The material thus obtained was ready for deposition.

EXAMPLE 3 Tantalum Oxide Hybrid Polymer 1

TaCl₅ (0.007342 mol) was placed to a round bottom flask and methanol(MeOH) (26 ml) was added. To the clear reaction solution Ta(OEt)₅(0.007342 mol) was added. The clear reaction solution was stirred atroom temperature for 2 h. Solvent exchange from MeOH to2-isopropoxyethanol (5×) was carried out using rotary evaporator(p=200-51 mbar, tbath=40° C.). The clear reaction solution was stirredat room temperature for a few minutes and after that the reactionsolution was neutralized using TEA (m=4.62 g; 0.04566 mol). The whitesuspension was stirred at room temperature for 2 h and then filtratedusing pressure filter (0.45 um). The clear solution obtained was placedin freezer overnight. After this the suspension was filtrated. Thesolvent used during the synthesis was removed by rotary evaporator(p=100-1 mbar, t(bath)=40° C., at 1 mbar for 10 min). 6.82 g ofIPA:MeOH:1-butanol solution (6:3:1) was added as processing solvent tothe material. Clear reaction solution had a pH of 7.14. The material wasready for deposition.

EXAMPLE 4 Tantalum Oxide Hybrid Polymer 2

TaCl₅ (0.04218 mol) was placed in a round bottom flask and MeOH (151.1ml) was added. The clear reaction solution was stirred at roomtemperature for 2 h. Solvent exchange from MeOH to 2-isopropoxyethanol(5×) was carried out using rotary evaporator (p=200-50 mbar, t(bath)=40°C.). The clear reaction solution was stirred at room temperature for afew minutes. The reaction solution was neutralized using TEA (m=14.82 g;0.14646 mol). The white suspension was stirred at room temperature for 2h and then filtrated using pressure filter (0.45 um). The slightlycloudy solution thus obtained was filtrated again using syringe andfilter (0.45 um). The resulting clear solution was placed in freezer andkept there overnight. After this the suspension was filtrated againusing a syringe filter (0.45 μm). The solvent was removed by rotaryevaporator (p=100-1 mbar, t(bath)=40° C., at 1 mbar for 10 min). 240wt-% of an MeOH: 1-butanol solution (1:1) was added as a processingsolvent. A clear reaction solution was obtained (pH=7.1). The materialwas ready for deposition.

Material Processing and Characterization

Processing (Example of Spin-on Deposition)

Metal Oxide High Refractive Index Polymers

For characterization purposes, the above-described metal oxide polymers(Polymer examples I, II and III) were used as optical thin films and,thus, the films were deposited on p-type 4″ silicon substrates byapplying the spin-on processing method. The solution was poured on astatic substrate after which the material was spun on the wafer in four(3) stages: first the solution was spread on the substrate at 50 rpmspeed for 10 seconds, then at 100 rpm speed for 10 seconds and finallyat 1500 rpm for 30 seconds. Edge bead removal (5 mm removal from thewafer edge) and backside rinse were accomplished manually using2-propanol as a rinsing solvent. The film curing after spin coating wasperformed in two steps. Initial film pre-bake was done at 130 C for 5minutes using a conventional open-air laboratory hot plate with ±2° C.temperature uniformity over the plate. After this the films were curedin oven (nitrogen atmosphere) using the following temperature cycle: A)30 minutes ramping to 250° C.; B) 60 minutes bake at 250° C.; C) 30minutes ramping to 400° C.; D) 60 minutes bake at 400° C.; E) 90 minutesramp down to room temperature. The optical characterization measurementsof the cured films were carried out using an ellipsometer.

Film Characterization:

The film thickness, refractive index and extinction co-efficient (k)measurements were performed by using SCl FilmTek 4000, which is aspectrophotometry-based metrology tool (see summary of data in Table 2).The spectral optical data was acquired from 450 nm to 1700 nm.

The stability of the cured films was characterized using an etching testwith potassium hydroxide KOH 10-w % (weight percent) solution at 50° C.for 5 minutes. All the films had good etch resistance against the KOHsolution without any changes in optical properties or morphology of thefilms. Adhesion on substrates, e.g. p-type silicon, glass and plastics(polypropylene, PMMA, polycarbonate) was also found to be good.

Table 2 summarizes the refractive index and k-values for the abovementioned metal oxide polymers (Examples 2-4). TABLE 2 Retractiveindices and extinction co-efficient (k) values (at 632.8 nm) for themetal and metalloid oxide polymer films. Extinction Polymer Filmthickness co-efficient (k) Refractive index material (nm) at 632.8 nm at632.8 nm Examples 2 70 nm k = 0.01573  n = 2.12291 Example 3 120 nm  k =0.0007  n = 2.0017 Example 4 96 nm k = 0     n = 2.0012Alternative Materials and Processing Methods

As mentioned above, other metal salts (in addition to titaniumtetrachloride) and/or alkoxides precursors can be used in the synthesisof these hybrid materials. Furthermore, it is also possible to chooseother organic (in addition to methacrylic acid) precursors to carry outthe synthesis and modify the properties of the resulting hybridmaterials.

For example, using tin tetrachloride as a metal precursor molecule avery similar optical film forming behavior was observed: 0.1 mol of tin(IV) chloride was reacted using the above described synthesis methodwith 0.1 mol of methacrylic acid. The synthesized tin oxide hybridpolymer was deposited from aqueous phase using spin coating (3000 rpm,30 s). The film was annealed at 200 C for 4 hours. The film resulted ina thickness of 85 nm with refractive index approximately of 2.0 at 632.8nm range. These films are also electrically conductive to some extentand their optical properties and conductivity can be tuned by codopingof the matrix with an other metal oxide component, such as antimonyoxide.

As described above these materials can be used as optical or electricalcoatings but also patterned for example using lithography, embossing,roll-to-roll printing and gravure printing. More specifically thematerial wherein carbon double bonds exists can be exposed to UV ordeep-UV light and thus carbon double bond reacts and cross-links andmaking the exposed parts non-dissolvable to an organic solvent(developer such as isopropanol). Therefore, the material is behaving asa negative type resist in the lithographic process.

Potential Applications for the Materials

As briefly discussed above, the present materials have a great number ofinteresting new applications. Examples include:

A. Optical and electrical coatings

B. High dielectric constant (high-k) gate oxides and interlayer high-kdielectrics

C. ARC (anti-reflection) coatings

D. Etch and CMP stop layers

E. Protection and sealing (OLED etc.)

F. Organic solar cells

G. Optical thin film filters

H. Optical diffractive gratings and hybrid thin film diffractive gratingstructures

I. High refractive index abrasion resistant coatings

These applications will be examined in more detail with reference to theattached drawings. In the drawings, reference numerals 100, 200, 300,400, 500, 525, 600, 800 and 900 are used to designate varioussubstrates.

Lithographic Processing Example

Negative Photolithography Process:

When the metal oxide precursor is modified with an organic moiety thatcontains radiation sensitive carbon double bonds, such as acrylates, thematerial can be polymerised by photo-crosslinking the organic compounds.

FIG. 4 shows the various steps of a typical lithographic processing ofnegative tone materials.

On a substrate (wafer) 100, a thin film layer 105 forming an optical canbe deposited by spin-on processing. A photomask 110 is thenalligned/placed on the thin film surface. The photomask layer isprovided with apertures for exposing the thin film layer topolymerisation typically carried out with high intensity radiation, suchas ultraviolet (UV), Deep UV or e-beam radiation, prior the finalformation of continuous metal-oxide backbone (“Exposure” in FIG. 1).Thus, optical and opto-electronic structures 105 are produced into thematerial via a photo-mask 110 in a single lithography-step directly onthe wafer surface without the need of any complex masking (typicallycarried with photo-resist) and etching steps.

The unexposed regions are thereafter removed during a chemicaldevelopment step (“Development” in FIG. 1), since those regions are moresolvable to a developer than the exposed photo-polymerised regions.Therefore, it can be stated that the material functions as a negativetone material.

Typical developer chemicals in the development step include organicsolvents such as 2-propanol, acetone, methyl isobutyl ketone or dilutedacids and bases or even various combinations of the previous compounds.After the development, the processing of the patterned structures aretypically finalised with by annealing the sample at elevatedtemperatures (“Postbake” in FIG. 1). This annealing process may includeda “burn-off” of the previously formed organic polymer matrix if theanneal temperature is higher than the decomposition temperature of theorganic polymer compounds. This “burn-off” anneal is preferable to beexecuted in oxygen containing atmosphere so that fully stoichiometricmetal-oxide matrix can be formed. However, other oxidative gasses canalso be applied, such as N₂O, CO and CO₂.

A. Optical and Electrical Coatings:

Based on the above, films produced from the present compositions can beused as optical or electrical thin coatings 105 on various substratesurfaces, such as glass, silicon, plastics, ceramics and laminates (suchas printed circuit board materials e.g. FR4). The films have opticalfunctionalities, such as properties of anti-reflection and relative highabsorption in the UV and DUV wavelength ranges (i.e. below 400 nm),and/or have thermal and/or electrical functionalities, such as thermalor electrical conductivity, high dielectric breakdown strength and highdielectric constant and combinations thereof. With certain metal oxidecompositions the materials are also conductive. This is the case inparticular when tin (Sn) is used to form the metal oxide matrix.

Coating film thicknesses can be varied from 1 nm to 2.0 μm depending onthe material composition, dilution ratio and deposition method andprocessing temperature.

When the material is synthesized it contains metal oxide as well asorganic functionality. Depending on the processing temperature the filmmay be amorphous or crystalline. At low processing temperatures theorganic functionality remains in the material and the film of amorphous.When the anneal temperature is increased (above about 300 to 350° C.,the organic residues are burnt off from the material film and only themetal dioxide remains in the film, but the material still remainsamorphous. When the anneal temperature is further increased (typicallyabove 600° C.), the material starts to crystallize and forms crystallinestructure characteristic for the metal oxide used in the synthesis.

The material can also be used as a high refractive index over-coating ontop of an optical topography, such as on a grating structure, to enhancethe diffraction properties of the grating. At the same time the materialis able to protect the optical topography from damage, since the coatingacts at the same time as an abrasion-resistant coating. Furthermore, thefilm can be used as a planar light-guide (i.e. two dimensionalwaveguide) or patterned light-guide (i.e. channel waveguide).

The advantage of using a high refractive index material in combinationwith lower index materials in light-guide components is that thedimensions of the component can be dramatically decreased and very highbending radiuses can be used due to the high refractive index differencebetween the high index light-guide and the surrounding claddingmaterials.

Due to the fact that the materials can be coated or deposited from theliquid phase optical and electrical coatings can be formed on top ofvarious shapes, such as on fibres or fibre tips as well as onflexible/bended surfaces, such as plastic foils using various depositionmethods.

B. High Dielectric Constant (High-k) Material

To build next-generation transistors, it is advantageous to work withmaterials that can replace the silicon dioxide gate dielectric whereincontinued thinning makes it increasingly difficult to control currentleakage. This thicker class of materials, known as “high-k,” willreplace commonly used silicon dioxide technology in high performancedevices. “High-k” stands for high dielectric constant, which is ameasure of how much charge a material can hold. Different materialssimilarly have different ability to hold charge. Air is the referencepoint for this constant and has a “k” value of 1. High-k materials, suchas hafnium dioxide (HfO₂), zirconium dioxide (ZrO₂) and titanium dioxide(TiO₂) inherently have a dielectric constant or “k” above 3.9, the k ofsilicon dioxide. The dielectric constant also relates directly totransistor performance. The higher the k, the greater the transistorcapacitance, which means that the transistor can properly switch betweenand “on” and “off” states, and have very low current in the “off” stateand yet a very high current when it is turned on. Typically, thethicknesses of these high-k materials vary in the range from about a fewnanometers to about 10 nm, whereas if silicon dioxide used the thicknessneeds to be as thin as 1 nm at 90 nm technology node size which isobviously difficult to process and control.

By using materials provided by the present invention, high-k materialscan be applied in a simple manner on various surfaces and topographiesat advantageously low processing temperatures as well as patternedsimply through direct lithographic patterning.

Conventionally, k-high materials are processed with CVD (Chemical VaporDeposition) and ALD (Atomic Layer Deposition), which require expensiveequipment as well as complex masking and etching schemes.

C. ARC (Anti-Reflection) Coatings

FIGS. 5 and 6 show the use of the present materials in the form of thinfilms as anti-reflection coating (ARC) layers during processing and ontop of finished device structures. More specifically, FIG. 5 shows howthe materials can be applied as BARC and TARC layers during lithographicprocessing, and FIG. 6 how the materials are applied as ARC layer(s) onoptical component surfaces.

Thus, the material can be applied as bottom antireflection layers 205and/or as top antireflection layers 215 to be used in lithographicprocessing. Reference numeral 210 in FIG. 5 stands for a film of resistmaterial.

The material can be used also on top 310 of optical structures 305 tofunction as antireflection coating layer. The processing can be tuned toresult in desired film thickness. The ARC layer film 310 thickness hasto be optimized for each structure and used wavelength separately.

D. Etch and CMP Stop Layers

The material can be also applied as a wet chemical and dry etching stoplayer in lithographic processing. It can be also used in chemicalmechanical polishing processing.

E. Protection and Sealing (OLED etc.)

The material can be used as protective coating of e.g. Organic LightEmitting Devices. FIG. 7 shows how the material can be applied 420 toovercoat/seal organic light emitting devices comprising a three-layerstructure with an anode layer 405, at least one organic layer 410 and acathode layer 415, deposited on a substrate 400.

F. Organic Solar Cells and Active Windows

The novel material can be also used as an efficiency enhancement orsolar energy activation layer 510 (cf. FIG. 8) for example in solarcells known as Titanium-Dye-Sensitized (TDS) cells.

TDS cells use 2 transparent sheets of glass 500, 525 with conductivecoatings and an electrolyte 505, 510, 515, 520 sandwiched inbetween,thus allowing them to be used as a window type solar panel. Referencenumeral 505 stands for an anode layer, 515 for organic layer(s) and 520for a cathode layer. FIG. 8 shows how the material can be used as anefficiency enhancement layer 510 between the anode 505 and organicmaterial 515. TDSs are at present producing electricity commercially atabout 10% efficiency and produce about 50 watts per square meter. Whenused as a window, they have the potential of being able to reduce theheat gain into a building and also provide power to it. Part of theattractiveness of this type of cell is the potentially low cost thereofand the relatively simple construction. It has an anatase crystallinestructure, and it is white to semi-transparent. The electrodes and theexposure to light are provided by a glass sheet sandwich with conductivecoatings. The titanium dioxide is treated with a synthetic rutheniumbipyridyl based dye on the incoming light surface and works inconjunction with an electrolyte of iodide/triiodide to the otherconductive surface to produce a voltage potential. The “back” layer hasa catalyst coating, such as carbon, on its SnO₂ layer. The photo-exciteddye injects an electron through the TiO₂ layer, which is passed to theSnO₂ surface and out to the external circuit. The SnO₂ layer isconductive because of the existence of oxygen vacancies which act asdonors. Within the iodide electrolyte it (iodide/triiodide) undergoesoxidation at the dye and regeneration at the catalyst coated SnO₂electrode on the opposite side, thus maintaining an electrolyte balanceand completing the circuit.

This type of solar cell will have superior performance particularly atlower light levels over the typical PV “semiconductor” types because itdoes not suffer from the electron-hole recombination in thesemiconductor material, which seriously affects the efficiency of PVcells.

G. Optical Thin Film Filters

The materials can be applied in stack thin film filter structures. FIG.9 shows example of a thin film filter. Two materials are needed forfabrication of a thin film filter: A high index material 605 (materialswhich can be produced according to the present invention) and a lowindex material 610 (e.g. SiO₂, methylsilsesquioxane and fluorinatedpolymers).

FIGS. 10 a and 10 b show how the stack filter can be tuned by heatingit. In the figures, the following reference numerals are used: 600substrate 605 high index layer 610 low index layer 700 bottom electrode705 top electrode 710 contact pads

FIG. 11 shows another example where the thin film filter idea isapplied. This construction can be made also thermally tunable like shownabove in FIGS. 10 a and 10 b. Reference numeral 805 depicts the highindex layer according to the present invention, and numerals 810 and 815stand for the low index layer and a thick material layer.

FIG. 12 shows a resonant cavity for an OLED (cf. FIG. 8) comprisingdeposited on a substrate 900 a high index layer 905, a low index layer910, an anode 915, an organic layer 920 and a reflective cathode 925.

H. Optical Diffractive Gratings and Hybrid Thin Film Diffractive GratingStructures Via Embossing, Holography Lithography and Nano-Imprinting

The coated, but not fully hardened, film can be patterned at very fineresolution by embossing (hot embossing and UV embossing are applicable),holography lithography or nano-imprinting. During embossing andnano-imprinting processing, the films are structured by pressingmechanically a patterned stamp or shim against the film surface, whichresults in replicated negative image of the stamp or shim to the film.The replicated structure is thereafter “frozen” by thermal and/or UVprocess while the mechanical stamp/shim is still in place or right afterremoving the mechanical stamp/shim. After the replication step iscompleted, additional treatments, such as solvent cleans, can beapplied. For the purposes of holographic lithography patterning the filmneeds to contain photo-crosslinkable components that are reacted, i.e.,cross-linked, in the course of the lithographic process. After theholographic lithography, use of additional chemical treatments istypically mandatory to remove unexposed areas of the film.

I. High Refractive Index Abrasion Resistant Coatings

A metal oxide backbone (such as Ti—O—Ti) generates very tough and hardfilm structure. On the other hand, the organic character of thematerials described in this invention provides excellent adhesion toplastic surfaces. To achieve a property known as abrasion resistantbehavior with thin films on relative weak plastic surfaces, hard, toughand good adherence is required. Also since the abrasion resistance filmsare typically deposited on thermally unstable substrate low processingand annealing temperatures are also required which is one of the keypurposes with the uses described for the present invention. It is alsopreferable that the abrasion resistant film has a high refractive indexso that it can be used as an anti-reflection coating and,simultaneously, as a protective film.

1. Method of forming a thin film on top of a substrate, comprising thesteps of applying on the surface of the substrate a composition obtainedby converting a complex metal oxide precursor composition into anintermediate product, which is dissolved in liquid phase and which canbe polymerized; forming a thin layer on the surface; removing thesolvent of the solution; and polymerizing the intermediate product intoa cross-linked film.
 2. The method according to claim 1, wherein thecomplex metal oxide precursor composition comprises at least two metaloxide precursors selected from the group of metal halogenides having theformula IMeX_(m),  I wherein Me stands for a metal, X stands for a halogenide andm represents the valence of the metal, and metal alkoxides, having theformula IIMeOR¹ _(m),  II wherein R¹ stands for a linear or branched, aliphatic oralicyclic alkyl group, which optionally is substituted by 1 to 3substitutents selected from the group consisting of hydroxy, carboxy,anhydride, oxo, nitro and amido groups, and Me and m have the samemeaning as above, or the complex metal oxide precursor compositioncomprises at least one metal compound selected from the group ofcompounds having the formula IIIX_(n)MeOR¹ _(p),  III wherein Me, X and R′ have the same meaning asabove and n is an integer 0 to m, p is an integer 0 to m, and the sum ofn+p is equal to m, m having the same meaning as above, or the complexmetal oxide precursor composition comprises a mixture of compoundsaccording to at least one of formulas I and II with at least onecompound of formula III.
 3. The method according to claim 1, wherein atleast one of the metal oxide precursors of the complex metal oxideprecursor composition is reacted with an organic compound, whichcontains at least one functional group capable of reacting with themetal element of the precursor, to produce an intermediate product,which is dissolved in liquid phase and which can be polymerized.
 4. Themethod according to claim 1, wherein the intermediate product isprocessed from aqueous liquid phase.
 5. The method according to claim 1,wherein the intermediate product is processed from liquid phase toproduce a film having a thickness in the range from 1 nm to 1000 nm withsingle deposition run.
 6. The method according to claim 5, wherein theintermediate product is processed at a temperature in excess of 500° C.to produce a film having a thickness below 500 nm to prevent filmfailure due to cracking.
 7. The method according to claim 1, wherein theintermediate product is processed to give a high refractive indexcoating.
 8. The method according to claim 1, wherein the thin layer isannealed at a temperature in the range of 80 to 350° C., to produce ametal oxide film which contains at least some residues of the organiccompound.
 9. The method according to claim 8, wherein the intermediateproduct is processed at a temperature of about 150° C. to give a filmhaving a refractive index of 1.9 or more and at 350° C. to giverefractive index of 2.0 or more.
 10. The method according to claim 1,wherein the organic compound contains radiation sensitive carbon doublebonds to allow for polymerization of the intermediate product byphoto-crosslinking.
 11. The method according to claim 1, comprisingforming a thin film on a substrate selected from the group of glass,plastics, paper, ceramics and laminates.
 12. The method according toclaim 1, comprising forming an optical or electrical thin film coatingon a substrate.
 13. The method according to claim 1, wherein the thinfilm forms a high refractive index film on top of a grating structure orit acts as a protective layer on top of the grating structure.
 14. Themethod according to claim 1, comprising forming a high dielectricconstant film.
 15. The method according to claim 1, comprising formingan anti-reflection coating.
 16. The method according to claim 1,comprising forming a chemical and dry etching stop layer in lithographicprocessing.
 17. The method according to claim 1, comprising forming aprotective coating in an organic light emitting device.
 18. The methodaccording to claim 1, comprising forming an efficiency-enhancing layerin a solar cell.
 19. The method according to claim 1, comprising forminga high index material in an optical thin film filter.
 20. The methodaccording to claim 1, comprising forming an optical diffractive gratingand hybrid thin film diffractive grating by embossing, holographylithography and nano-imprinting of the thin film.
 21. The methodaccording to claim 1, comprising forming a high refractive indexabrasion resistant coating.
 22. The method according to claim 1, whereinthe thin film is deposited on the substrate by spin-on deposition. 23.The method according to claim 1, wherein intermediate product is capableof polymerizing under the influence of heat and optionally evaporationof solvent.
 24. The method according to claim 1, wherein theintermediate product is capable of polymerizing to form a cross-linkedpolymer having a molecular weight in excess of 5,000 g/mol and up to250,000 g/mol.
 25. A method of forming a metal oxide precursorcomposition, comprising the steps of providing at least two startingreagents, at least one of which comprises a metal oxide precursor;reacting the reagents with each other to form a reaction productcomprising a modified metal oxide precursor; recovering the reactionproduct; and reacting the reaction product with a compound selected fromthe group of organic compounds, water and aqueous solutions, forconverting the reaction product into an intermediate product which issuitable for liquid phase processing.
 26. The method according to claim25, wherein the reagents comprise metal oxide precursors which havedifferent or the same metal element and which are formed by halogenidesor alkoxides or combined precursors having both halogenides andalkoxides as ligands.
 27. The method according to claim 25, wherein thereaction is carried out in an inert solvent, which optionally is removedafter the reaction.
 28. The method according to claim 25, wherein thereagents comprise at least one metal element precursor and a reactivesolvent.
 29. The method according to claim 25, wherein the reactionproduct is reacted with organic compounds to form different complexes,or with water or acidic water to induce hydrolysis and condensation ofthe metal oxide precursors.
 30. The method according to claim 25,wherein reaction product is neutralized.
 31. The method according toclaim 25, wherein any acidic side products are neutralized and removed.32. The method according to claim 25, the intermediate reaction productis filtrated using, e.g., pressure filtration or recirculationfiltration.
 33. The method according to claim 25, wherein the reactionproduct is recovered in aqueous solution.
 34. The method according toclaim 25, wherein the reaction product is recovered in the solutionformed by an organic solvent and dissolved into an aqueous phase bysolvent displacement.
 35. The method according to claim 25, wherein thereaction product is recovered in aqueous solution and dissolved into anorganic solvent having a boiling point higher than water by solventdisplacement.
 36. The method according to claim 35, wherein the reactionproduct is dissolved in a cyclic ether, such as gamma butyrolactone. 37.The method according to claim 25, wherein the organic compound iscapable of stabilizing the metal oxide precursor to the extent that itdoes not form a fully cross-linked polymer matrix, which would not besolvable in an aqueous or organic solvent.
 38. The method according toclaim 25, wherein the organic compound is an organic compound selectedfrom the group consisting of organic acids, acid anhydrides, alkoxides,ketones, beta-diketones, acetyl acetones, benzyl acetones, aryl oxides,beta-keto-esters, alkanol amines, glycols, oximes, alkyl hydroxylamines,beta-keto-amines, Shiff-bases, thiols and aldehydes.
 39. The methodaccording to claim 25, wherein the organic compound contains carbondouble bonds.
 40. The method according to claim 39, wherein the organiccompound is selected from the group consisting of acrylic acids,(alk)acrylic acids, acetic acid, trifluoro acetic acid andbeta-diketone.
 41. The method according to claim 25, wherein the molarratio between the metal oxide precursor and the organic compound isabout 10:1 . . . 1:10, preferably about 5:1 to 1:5.
 42. The methodaccording to claim 25, comprising preparing a single metal oxideprecursor composition or a complex, multi-metal oxide precursorcomposition.
 43. Method of producing a film forming composition, whichcan be applied on a substrate to form a metal oxide film on thesubstrate, comprising the steps of providing a precursor of the metaloxide material, containing a metal element, providing an organiccompound, which contains at least one functional group capable ofreacting with the metal element of the precursor, reacting the precursorwith the organic compound to provide a reaction product; and recoveringthe reaction product, the precursor comprising two or more metalhalogenides of the formula IMeX_(m),  I wherein Me stands for a metal, X stands for a halogenide andm represents the valence of the metal, or two or more metal alkoxides,having the formula IIMeOR¹ _(m)  II wherein R¹ stands for a linear or branched, aliphatic oralicyclic alkyl group, which optionally is substituted by 1 to 3substitutents selected from the group consisting of hydroxy, carboxy,oxo, nitro and amido groups, and Me and m have the same meaning asabove, said halogenides or alkoxides having different metal elements Me,or mixtures of metal oxide halogenides/alkoxides of formulas I or II ora metal halogenide or metal alkoxide, which in itself contains twodifferent metal atoms.